“…organizing the contents of the mass storage device used to store files into the smallest number of contiguous regions (fragments). It also attempts to create larger regions of free space using compaction to impede the return of fragmentation.”

As simple as that: Defragmentation is the fix for fragmentation.

Why “defragmentation”? Well, it all starts with the word “fragment”; whenever a file is being stored in a storage device, there is a chance of it not being able to exist as one continuous block, but instead since there may be files in the way, the file is divided in as many parts as necessary, AKA, fragmented.

What you do when you defragment is fix this fragmentation, merging the files that are separated into one continuous block. There are many different methods that disk defragmenters use when doing it’s job, but the popular consensus is moving all files to the beginning of the disk. This is done for two different reasons: (1) New files will be created after the defragmented ones, and (2) the hard drive head won’t travel to the end of the disk searching for files, making it faster to get your files, AKA, better disk performance.

And this is something important to keep in mind, Disk Performance. What exactly disk performance is? Well, a very raw way to explain it simple is “Read/Write Speed”. That’s it, the improvement when reading from and writing into a storage device.

Of course, lately, this is not that necessary nor urgent. With the coming of flash drives and SSD drives defragmenting is becoming less relevant and users don’t feel the need to defragment because the read/write speeds are quite awesome considering the old IDE drives.

But again, disk performance, how it improves overall performance?

Reading: each time you open Computer, or want to see the size of a folder, or try to see the thumbnail of an image, you are making requests to the hard drive to read these files and show them to you, whether if it’s the size of a file or your beach photos. A faster reading can give you faster responses.

Writing: when you create a file, install a program, or open a website, you are storing files into your drive, that at some level can be compared to burning a CD. A faster writing can give you, again, faster responses.

Defragmentation can improve both speeds, can put files into one chunk and into an specific region of the disk, making these easy to read. And since files are not scattered, files can be written in one continuous block instead wasting time separating them.

In conclusion, unlike the old debunked myth of cleaning your registry, Defragmenting your drive can, in fact, improve your disk performance. If you have an SSD drive, you have no obligation to do this at all.